1. Field of the Invention
The present invention relates to a power converter and, more specifically, to a power converter controller IC (integrated circuit) that has an input voltage pin with multiple functions.
2. Description of the Related Art
With the explosive growth of the number of electronic devices recently, the demand for power converters used as adapters or changes for these electronic devices is also growing at a rapid rate. These power converters are typically controlled by power converter controller ICs. Especially, switching mode power converters are typically controlled by power converter controller ICs that control the on-times (TON) or off-times (TOFF) of the switch in the power converters to regulate the output voltage and power of the power converters.
The power converter industry is under significant pressure to manufacture power converter controller ICs that are highly efficient but can also be manufactured at low cost. Because the manufacturing cost of ICs is highly dependent upon the die size, the number of pins, the packaging, and testing of the IC, it is desirable to reduce the number of pins of an IC. However, it is difficult to reduce the number of pins in conventional power converter controller ICs, because in conventional power converter controller ICs each pin of the IC is associated with a single, separate parameter or function and thus the IC required as many pins as the number of parameters or functions either input to or output from the controller IC. Thus, it is difficult to reduce the number of pins in the power converter controller IC without reducing the number of parameters either input to or output from the controller IC and thereby sacrificing the performance of the power converter.
Therefore, there is a need for a technique to reduce the number of pins used in a power converter controller IC and reduce manufacturing costs of the IC without reducing the number of parameters or sacrificing the performance of the power converter.